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Basis of Presentation (Details) $ in Millions	3 Months Ended
Basis of Presentation (Details) $ in Millions	Dec. 31, 2018 USD ($) Segment	Dec. 31, 2017 USD ($)	Oct. 01, 2018 USD ($)	Sep. 30, 2018 USD ($)
Number of Countries in which Entity Operates	180
Number of Reportable Segments \| Segment	2
Retained earnings	$ 18,916			$ 18,561
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	$ 1	$ 1
Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition, Description	-106
Accounting Standards Update 2016-16 [Member]
Retained earnings			$ 165
Accounting Standards Update 2016-01 [Member]
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax			$ 54
Accounting Standards Update 2017-07 [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)		$ 1
Calculated under Revenue Guidance in Effect before Topic 606 [Member] \| Accounting Standards Update 2014-09 [Member]
Contract with Customer, Right to Recover Product, Current	$ 70
Retained earnings	$ 101
Minimum [Member] \| Accounting Standards Update 2016-16 [Member]
Amortization Period of Deferred Tax Assets	12 years
Maximum [Member] \| Accounting Standards Update 2016-16 [Member]
Amortization Period of Deferred Tax Assets	15 years